1. Field of the Invention
The present invention relates to a silver halide color photosensitive material. More specifically, the present invention relates to a silver halide color photosensitive material with high sensitivity minimal in graininess and excellent in storability.
2. Description of the Related Art
For a long time there has been a desire to make a silver halide color photosensitive material highly sensitive without increasing graininess. In general, sensitivity is dependent on the size of silver halide emulsion grains. The larger the emulsion grain, the greater the sensitivity is. However, since the graininess is increased in accordance with the increase in the size of the silver halide emulsion grains, there is a trade-off between sensitivity and graininess. In the industry, it is the most basic and important matter from the viewpoint of improving the image quality of a photosensitive material to increase the sensitivity without increasing the graininess.
There has been disclosed a technique of increasing the sensitivity without increasing the graininess by containing a compound having at least three hetero atoms in a silver halide color photosensitive material (see, for example, Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-)2000-194085, JP-A-2003-156823 and JP-A-2004-226971).
In contact, the present inventors have found that a compound having one or two hetero atoms obtains preferably better effect for improving the sensitivity than the above-mentioned compound at least of three hetero atoms and have extensively studied Improvement.
However, although the increase in sensitivity is obtained by the above-mentioned method, it has been clarified that the storability of a raw photosensitive material is occasionally degraded extremely. In particular, the storability of a photosensitive material in an environment of high temperature and low humidity such as the inside of an automobile left alone in the sun, occasionally a serious situation provokes, and it has been clarified that fog increase and sensitivity decrease are problems when the material is left alone at a temperature of 80° C. or more and a humidity of 10% or less.